Forging compound



Patented Mar. 28, 1944' FORGING COMPQUND Walter D. Hudson, Chicago,Ill., assignor to The ware Hodson Corporation, a corporation of Dela- NoDrawing. Application August 12, 1941, Serial No. 406,523

3 Claims.

The present invention relates to improvements in lubricating compounds,and is more particularly directed to improvements in graphitecontainingoils which are intended for application to hot forging and piercing diesand to other tools for use in the hot forging of metals, also at timesto the piece to be forged, such as iron, steel, copper, brass andaluminum, for the lubrication of extrusion dies in which such metals asaluminum, copper, brass and the like are extruded through heated diesand'for application to the metal being worked in such forging, piercingand extrusion operations.

In the preparation of such lubricating compounds, it is important tosecure a uniform and stable suspension of large quantities of graphitein the lubricant, since at the high temperatures at which the compoundsare used, the oil used as the vehicle is largely dissipated and thegraphite remains as the principal lubricant. In compounds as hithertoproduced, the graphite tends to settle out, resulting in a lack ofuniformity in the lubricant, which results in the lack of uniformity inits effectiveness when used. The lubricant compound is applied byswabbing, mechanical spreading or spraying, and uniformity in itsstructure and graphite content is important which may be applieduniformly by swabs, brushes or sprays, and which in use and on contactwith the hot forging or metal being worked, dissipate its oil componentand leaves a residue on the die or tool in which the graphite isuniformly distributed and does not cake or build up. In the product iiithe present invention, the graphite used is maintained in uniformsuspension in an oil having a colloid structure built up by the use ofa. gel-forming soap of a metal other than an alkali metal or alkalineearth metal, and I am able to use substantially larger proportions ofgraphite than have hitherto been employed in such compounds. In carryingout the invention, I preferably prepare a highly concentrated or basematerial of very high graphite content,

which may be readily converted into a final product or compound of-thedesired graphite content The graphite employed may be amorphous,

flake or defiocculated graphite. The oil employed is a lubricant mineraloil, preferably a distillate oil, of any desired viscosity. I prefer toemploy the lighter oils, ranging from a viscosity of 50 to 100 secondsSaybolt at 100 F. upwardly, say to 300 to 350 seconds Saybolt at 100 F.,since heavier oils are objectionable in use on account of smoke and charformation. In general I prefer to employ a parafiin distillate oilsubstantially free from wax and having a viscosity in the order of 50 to100 seconds Saybolt at 100 F. and preferably of to seconds Saybolt. Bythe present invention I am enabled to use lighter oils than thosehitherto used in such compounds, in which high viscosity of the oil wasrelied upon to retard settling of the graphite. Such heavy oils ashitherto used burned slowly with the evolution of considerablequantities of smoke and soot and left a tarry deposit on the work or dieto which the lubricant was employed. By the present invention I amenabled to use light oils, while maintaining the graphite in uniformsuspension.

On use of the compound of the present invention,

the light oil flashes quickly and cleanly or substantially completely onapplication to the hot die, tool or work, and does not leaveobjectionable tarry deposits which cause caking of the graphite.Furthermore, the compound produced in accordance with the presentinvention can be readily applied in a uniform, thin layer for effectivelubrication by mechanical sprayers, with great 15 to 20% of graphite inwhich case I first prepare a base compound of greater graphite content,say 30 to 60%. A minor proportion of the metallic soap is used,suflicient to produce from 1 to 5% in the final product. Thus, asuitable base compound may contain 24 to 36% of a light paraflindistillate oil of a viscosity of about 80 seconds Saybolt at 100 F., 4to 6% aluminum stearate and 30 to 40% of graphite. 1 preferably placethe-oil in a container provided with an agitator, and add successivelythe aluminum stearate and the graphite, stirring each in thoroughly. Themixing of the base is done without theapplication of heat. The resultingmixture, which constitutes the base compound, is then drawn oil, andallowed to stand, preferably for in excess of one day. It may be storedfor later use in preparing the final compound, or the base compound maybe shipped, the process of preparing the final compound being completedat the point of use. The retention of the constituents of the mixture incontact with each other for a normalizing period, of say, 6 to 8 hoursupwardly, and prefer ably at least 2 or 3 days, has a decidedlybeneficial effect upon the character of the final product in securinggreater stability with respect to the maintenance of uniform dispersionof the graphite therein.

In preparing the final product, the base compound, prepared asdescribed, is placed in an agitator provided with suitable heatingmeans, and the necessary amount of oil (preferably, a light oil of thesame character as that used in the base compound) is added to secure thedesired final product, which, in the case of the specific illustrativeexample, may be one containing 15 to 20% graphite. The agitator isoperated to secure thorough admixture of the base compound and the oiland heat is turned on and gradually increased so that a temperature inthe order of 250 to 350 and preferably of 2'75 to 300 is reached inabout 6 hours. The mixture is held at that temperature for an additionalperiod of 20 minutes or longer, say 30 minutes, the batch being thencompleted. It is drawn off into suitable containers and allowed to setfor some time, say for 2 or-3 days or longer, in which period a morepermanently stable structure appear to be formed. In the illustrativeexample, the use of an equal quantity of oil will result in a finalproduct of 15 to 20% graphite concentration. Occasionally, on standingfor a considerable period, there may be a slight bleeding of the oil,which can be poured off if desired, or can be stirred into the mixturewhen it is used without destroying its structure.

The resulting compound has a stable colloid structure and the graphiteis uniformly suspended therein. Hence, it can be applied manually with abrush, spreader or dauber, or may be sprayed upon the piece-or the dieused for forging or extrusion. It may be applied evenly withoutdifiiculty, for example, by suitable spray mecham'sm, securing uniformdistribution of the graphite. As a result, great savings are made in theuse of the compound ofthe present invention over those hitherto known,of which the use of large quantities were necessary to secure thepresence of adequate amounts of graphite. Thus in many cases I am ableto secure adequate lubrication, using from one-third to one-tenth thequantity of compound as compared with that previously used.

Although in the example given; the amount .specific requirements of theuser.

present invention has been described in connecof oil subsequently addedis equal to the amount of the base compound, it will be understood thatthese proportions may be varied widely. Thus, in the case of a finalproduct with a high graphite content, say in the order of 30 to 40%, alarger proportion of graphite may be incorporated in the base compoundand a smaller proportion of oil added after the normalizing period, orperiod of retention of th base compound. The base compound may suitablycontain from 1.5 to 10% of the gel forming soap and from 10 to 75 or ofgraphite, to be diluted with oil as heretofore described to secure thedesired proportions of graphite in the final product.

- In use, the heat of the metal,'die or tool with which the compound isbrought in contact quickly burns oif substantially all the oil, leavingas a a residue the mixture of aluminum stearate and graphite, probablywith some minute quantity of mineral oil. By the use of light oils asheretofore described, the oil flashes ofi quickly and cleanly, leavingthe graphite-containing residue desired for lubricating purposes inplace. The colloid structure of the compound is such that thisgraphite-containing residue is uniform, is effective in securing desiredlubricant action and preventing sticking to the die, and the residuedoes not cake or build up when the die is used. As a result, sticking ofthe forgings and checking and cracking of the die are avoided, resultingin less detective work and in longer life of the dies.

It will be readily understood that the proportion and nature of thegraphite employed, the character of the mineral oil and the proportionof the metallic soap used in securing a desired structure may be variedin accordance with the Although the tion with a specific examplethereof, it is to be understood that it is not limited to the details ofthe example given, except in so far as included in the accompanyingclaims,

I claim:

1. A stable colloidal base compound used in preparing a stable lubricantcomposition for use on dies and tools operating on highly heated metalwhich consists of a light lubricant hydrocarbon oil of 50 to secondsSaybolt viecosity at 100 F., from about 10to 80% of graphite and fromabout 1.5 to 10% of aluminum soap, said oil being maintained in the formof a stable colloidal gel structure by said metallic soap with thegraphite uniformly and relatively permanently dispersed and suspendedtherein, the said base compound being capable, on dilution with oil ofthe same viscosity and on heating and mixing therewith, of forming thesaid lubricant with the graphite uniformly suspended therein.

2. A stable colloidal lubricant compositionsuitable ior use on dies andtools operating on highly heated metal which comprises a substantiallywaxfree, lightlubricant hydrocarbon oil of at least 50 to 100 secondsSaybolt viscosity at 100 from about 10 to 80% of graphite and from 1.5to 10% of aluminum soap, said oil being maintained in the form of astable colloidal gel structure by said metallic soap with the graphiteuniformly and relatively permanently dispersed and suspended therein,the said lubricating composition being capable, on dilution with oil ofthe same viscosity-and on heating and mixing therewith, of maintainingits stability with the graphite uniformly suspended therein.

3. A stable colloidal lubricant composition suitable for use on diesandtools operating on highly heated metal which comprises a lightlubricant hydrocarbon oil of at least 50 to 100 seconds Sayboltviscosity at 100 F., from about 10 to 80% oi. graphite and from about1.5 to 10% of a heavy metal soap, said oil being maintained in the formof a stable colloidal gel structure byv said heavy metal soap with thegraphite uniformly and relatively permanently dispersed and suspendedtherein, the said lubricating composition being capable, on dilutionwith oil of the same viscosity and on heating and mixing therewith, ofmain taining its stability with the graphite uniformly suspendedtherein.

. WALTER D. HODSON.

